I am playing around and I am having trouble getting the same rendering results across all octane and unity windows.Is it the Unity - Player Settings - "Linear" Color Space? .. I hope not, since we are using in all our projects linear color space...

I have run into the same situation regarding the different display views between the PBR Viewport and the Node Editor. Do you know when you will implement a fix for that? It makes the workflow really unsuitable in several aspects, would be great to have a workaround as soon as possible.